This application is related to and claims priority from Japanese Patent Applications No. Hei. 11-240176 filed on Aug. 26, 1999, No. Hei. 11-274726 filed on Sep. 28, 1999, No. Hei. 11-320194 filed on Nov. 10, 1999, No. 2000-79357 filed on Mar. 16, 2000, and No. 2000-105380 filed on Apr. 3, 2000, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a vehicle air conditioner which automatically controls temperature within a passenger compartment to a set temperature by using a non-contact temperature sensor.
2. Description of Related Art
A conventional vehicle air conditioner described in JP-A-5-178064 includes a temperature setting unit for setting temperature of a passenger compartment to a passenger""s desirous temperature, an inside air temperature sensor for detecting temperature of inside air inside the passenger compartment, an outside air temperature sensor for detecting temperature of outside air outside the passenger compartment, a sunlight sensor for detecting an amount of sunlight entering the passenger compartment, a skin temperature sensor (non-contact temperature sensor) for detecting skin temperature of a passenger. In the conventional air conditioner, a target temperature of air blown into the passenger compartment or a target voltage applied to a blower is calculated based on signals from the temperature setting unit and the sensors. Further, to actually detect the skin temperature, the skin temperature sensor is disposed to only detect the head part of the passenger. However, in the conventional vehicle air conditioner, because four sensors are used for calculating the target temperature of blown air or the target blower voltage, product cost becomes higher. When the number of the sensors is simply reduced, control performance of the temperature of the passenger compartment may be greatly decreased.
In view of the foregoing problems, it is an object of the present invention to provide a vehicle air conditioner which can accurately control temperature inside a passenger compartment by effectively using a non-contact temperature sensor even when number of sensors is reduced.
It is an another object of the present invention to provide a vehicle air conditioner which controls temperature inside the passenger compartment to correspond to temperature feeling of a passenger, by effectively using a non-contact temperature sensor.
It is a further another object of the present invention to provide a vehicle air conditioner which prevents air-conditioning feeling for a passenger from being deteriorated due to an error-detection.
According to a first aspect of the present invention, a control unit of a vehicle air conditioner includes a temperature setting unit for setting a temperature of the passenger compartment to a set temperature, and a non-contact temperature sensor which detects a surface temperature of a predetermined detection range of the passenger compartment. The predetermined detection range of the non-contact temperature sensor includes at least one of a first detection portion in which a surface temperature is changed to approximately correspond to an inside air temperature inside the passenger compartment, a second detection portion in which a surface temperature is changed in accordance with an outside air temperature outside the passenger compartment, and a third detection portion in which a surface temperature is changed in accordance with a sunlight amount entering the passenger compartment. In the air conditioner, the control unit calculates the target air temperature at least using the set temperature from the temperature setting unit and a detection surface temperature detected from the non-contact temperature sensor. Accordingly, it is possible to output an environment signal relative to the inside air temperature, the outside air temperature and the sunlight amount entering the passenger compartment from the non-contact temperature sensor; and therefore, temperature of the passenger compartment is controlled to a suitable temperature corresponding to the inside air temperature, the outside air temperature and the sunlight amount. As a result, even when the number of sensors is reduced in the vehicle air conditioner, it can prevent air-conditioning performance from being deteriorated by using the non-contact temperature sensor.
Preferably, the non-contact temperature sensor is disposed to detect a surface temperature of detection subjects of a windshield, a clothed portion of a passenger, a seat and a ceiling of the passenger compartment. Further, each area ratio of the detection subjects to an entire detection area of the non-contact temperature sensor is set so that the area ratio of the windshield is (25xc2x110)%, the area ratio of the clothed portion and the seat is (35xc2x110)%, the area ratio of the ceiling is (20xc2x110)% and the area ratio of the other portion is (20xc2x110)%. Thus, a variation amount of the detection surface temperature, changed relative to heat load such as the inside air temperature, the outside air temperature and the sunlight amount, can be made close to a, target value. Accordingly, control performance of the passenger compartment is improved.
More preferably, each area ratio of the detection subjects to the entire detection area is set so that the area ratio of the windshield is (25xc2x15)%, the area ratio of the clothed portion and the seat is (35xc2x15)%, the area ratio of the ceiling is (20xc2x15)% and the area ratio of the other portion is (20xc2x15)%. Accordingly, control performance of the passenger compartment is further improved.
Further, the control unit includes temperature variation determining means for determining whether or not a variation amount of the surface temperature is larger than a set value, and the control unit controls an air-conditioning operation based on a determination of the temperature variation determining means. Therefore, the air-conditioning operation is suitably controlled to correspond to a variation of the detection surface temperature.
Preferably, the air conditioner further includes an air amount adjustment unit for adjusting an air amount blown into the passenger compartment from an air duct, the control unit controls the air amount adjustment unit so that the air amount blown into the passenger compartment from the air duct becomes a target air amount, and the control unit corrects the target air amount based on the determination of the temperature variation determining means. Therefore, it can prevent an outer disturbance from being affected to an air-conditioning operation.
Alternatively, the control unit corrects the surface temperature based on a determination of an outer disturbance determining means. Therefore, it can prevent an outer disturbance from being affected to an air-conditioning operation. For example, when the outer disturbance is determined by the outer disturbance determining means, the control unit controls an air-conditioning operation based on a previous surface temperature before being affected by the outer disturbance.
According to an another aspect of the present invention, a vehicle air conditioner includes a non-contact temperature sensor for detecting a subject surface temperature of a detection subject of the passenger compartment, operation control means which controls operation of the air conditioning unit based on the subject surface temperature detected from the non-contact temperature sensor, and output control means which controls an output timing for outputting the subject surface temperature into the operation control means. The output control means controls the output timing in accordance with a variation of the subject surface temperature. Thus, even in a case where the variation of the subject surface temperature is caused due to an error-detection, when the subject surface temperature is output to the operation control means after a difference between the temperature of the passenger compartment and the subject surface temperature becomes smaller, a deterioration of the air-conditioning feeling due to an error detection is restricted.
According to a further another aspect of the present invention, a vehicle air conditioner includes a non-contact temperature sensor for detecting temperature of a detection subject of the passenger compartment, correction means for correcting the temperature detected by the non-contact temperature sensor to a correction temperature, and control means which controls operation of an air conditioning unit based on the correction temperature from the correction means. Therefore, even when the temperature is error-detected by the non-contact temperature sensor, because the temperature detected by the non-contact temperature sensor is corrected by the correction means, a deterioration of the air-conditioning feeling, due to an error detection is restricted, and an air-conditioning control corresponding to a passenger""s feeling is performed.